Adhesive comprising reaction product of gamma-isocyanatopropyltriethoxy silane and a thermoplastic polyester

ABSTRACT

A water-activatable adhesive useful for adhering a solar film, polyester (polyethylene terephthalate) film, to glass. The adhesive comprises the reacted product of (A) gamma-isocyanatopropyltriethoxy silane, containing a free isocyanate (NCO) group, and (B) a thermoplastic polyester formed by reacting (i) a dibasic acid selected from the group consisting of terephthalic acid, isophthalic acid and hexahydrophthalic acid, and mixtures thereof, with (ii) a polymethylene glycol of the formula HO(CH 2 ) x  OH where x is an integer from 2 to 10, neopentyl glycol and glycerin, and mixtures thereof, and (iii) an aliphatic dibasic acid selected from the group consisting of those having the formula HOOC(CH 2 ) n  COOH where n is an integer from 1 to 8, and mixtures of such acids, whereby substantially no free NCO remains in the adhesive. 
     Solar film is used for absorbing and/or reflecting solar radiation. Solar film can be a single sheet of polyester dyed sufficiently to absorb the glare of bright sunlight, or it can be a single sheet of polyester, on one side of which a reflective metal (most often aluminum) is deposited in an amount which can be totally reflective or in an amount which still allows visible light transmission and over which a protective coating is deposited, or it can be a laminated structure of the reflective film adhered to a clear or dyed polyester film by which means the reflective metal is sandwiched between two layers of polyester film, or it can be a laminated structure of a reflective film to a polyolefin film.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The field of this invention is generally that of adhesives useful for bonding solar film.

2. Description of the Prior Art

Flexible polymeric substrates have been adhered to dissimilar substances, particularly glass, by a variety of adhesives. The need for adhering polymeric substrates to glass arises as one of a variety of concerted efforts in recent years to conserve energy. In hot weather, it is important to reduce the transmission of sunlight into a room while still maintaining adequate visibility.

Obviously, the less radiation which enters a room, the less need for energy expenditures for air-conditioning. One way in which this has been accomplished is by the use of reflective film, so-called "solar film", which is adhered directly onto window glass.

The common type of solar film comprises a base sheet of a transparent polyester, usually a polyethylene terephthalate film, onto one side of which a thin but reflective and transparent layer of aluminum has been vapor-deposited. It is of course possible to provide solar films with coatings of metals other than aluminum thereon. Onto the metal surface either a protective coating may be applied or a polymer film, usually polyester, dyed or clear, may be laminated with the use of a polymeric adhesive. Solar films are described in U.S. Pat. Nos. 4,157,417; 3,681,179; 4,095,013, and 3,152,950.

There is also another variety of solar film in use which does not have a metallic coating thereon, but which is dark in color and functions to exclude glare. This type is referred to in the trade as "dark smoke".

Thus, when a partially reflective solar film is in place, sunlight is partially reflected at the surface of the window with the result that there is a significant reduction in the amount of sunlight entering and thereby heating a room.

Various adhesives and adhesive systems have been described for adhering solar film to window glass. U.S. Pat. No. 3,290,203 (Antoneon and Berger) discloses water-activatable adhesives comprising casein, glue, polyvinyl alcohol and vinyl ether polymers.

U.S. Pat. No. 3,152,950 (Palmquist) discloses the use of a pressure-sensitive adhesive compound of a rubbery butadiene-acrylonitrile polymer and a phenol-formaldehyde resin.

U.S. Pat. No. 3,308,004 (Rouault) discloses translucent panels having a protective coating of reinforced crosslinked polyester resin.

U.S. Pat. No. 3,619,335 (Bryan) discloses laminates having a removable flexible polymeric film plasticized with a nonionic surfactant.

U.S. Pat. No. 3,681,179 (Theissen) discloses the use of a water soluble film-forming material which is deposited over a pressure-sensitive adhesive layer on the aluminum coated side of solar film. The water soluble film-forming material includes ethyl cellulose, or vinyl ether-maleic acid copolymer, or an ethylene oxide polymer.

U.S. Pat. No. 4,095,013 (Burger) teaches the use of a cling adhesive comprising a plasticized solvent-soluble copolymer consisting of vinyl chloride copolymerized with vinyl acetate, vinyl alcohol, or dibasic acid, or vinylidene chloride-acrylonitrile copolymer.

U.S. Pat. No. 4,146,585 (Ward) teaches a process for producing a silane grafted copolymer which comprises reacting a silane with vinyl chloride, hydroxyalkyl acrylate and a polymerizable monomer selected from the group consisting of alkyl esters of alpha, beta ethylenically unsaturated carboxylic acids and vinyl esters of saturated fatty acids.

U.S. Pat. No. 4,157,417 (Murphy) discloses an adhesive for a solar film wherein the adhesive comprises a physical mixture of an alkyl monoester of poly(methyl vinyl ether/maleic anhydride) and a silane such as beta-3,4(epoxycyclohexyl)ethyltrimethoxysilane or gamma-glycidoxypropyltrimethoxysilane with certain diols and aryl ethers.

U.S. Pat. No. 4,031,120 (Gervase) teaches the use of isocyanato organosilanes in combination with polyisocyanates and polymeric materials as adhesive materials for bonding vulcanizable elastomers at elevated temperatures to inorganic substrates.

Thus, there is a continuing need for an adhesive which can be applied directly to solar film for adherence to window glass and which will provide early and long-term bond strength upon exposure to sunlight, heat and humidity.

It is therefore the principal object of this invention to provide adhesive compositions which can be applied directly to solar film for direct adherence to window glass, which adhesives exhibit good early bond strength and excellent bond strength upon long-term exposure to sunlight, heat and humidity.

SUMMARY OF THE INVENTION

Broadly, the present invention relates to an improved, water-activatable adhesive composition for bonding solar film, through either its polyester base or metal-coated surface, to window glass for the purpose of reflecting sunlight from the window, with the beneficial result that sunlight radiation into the interior of a room is significantly reduced. The adhesive, which is useful for adhering polyester film, and hence solar film, to glass, comprises the reacted product of (A) gamma-isocyanatopropyltriethoxy silane, which contains a free NCO group, and (B) a thermoplastic polyester formed by reacting (i) a dibasic acid selected from the group consisting of terephthalic acid, isophthalic acid, and hexahydrophthalic acid and mixtures thereof, with (ii) a polymethylene glycol of the formula HO(CH₂)_(x) OH where x is an integer from 2 to 10, neopentyl glycol and glycerin, and mixtures thereof, and (iii) an aliphatic dibasic acid selected from the group consisting of those having the formula HOOC(CH₂)_(n) COOH where n is an integer from 1 to 8, and mixtures of such acids, whereby substantially no free isocyanate (NCO) remains in the adhesive. Gamma-isocyanatopropyltriethoxy silane, also known by its CAS name as Silane, 3-(Isocyanato)propyl triethoxy, is an organo functional silane which is commercially available under the trade designation "Silane Y-9030" from Union Carbide Corporation. It is a corrosive liquid which must be handled with care since it presents severe skin, eye and inhalation hazards.

It has been found that when gamma-isocyanatopropyltriethoxy silane, hereinafter referred to as "Silane", is reacted with a particular group of thermoplastic polyesters so that substantially no free isocyanate (NCO) remains, an adhesive composition is formed which can be coated onto a polyester film, or onto the polyester or metal-coated side of solar film, and the adhesive-coated film adhered to window glass to form a strongly adherent film thereon which remains bonded upon long exposure to sunlight, even under conditions of elevated temperatures and high humidity. One important property of the adhesive of this invention is its relatively early bond strength which improves with age.

The following are examples of the thermoplastic polyesters with which Silane is reacted:

    ______________________________________                                         Trade Designation and Source                                                                    Composition                                                   ______________________________________                                         Available from   Formed by reacting and                                        E. I. Du Pont de Nemours &                                                                      polymerizing 1,3-benzene-                                     Company          dicarboxylic acid (isophthalic                                                 acid), 1,4-benzene dicarboxylic                                                acid (terephthalic acid), 1,2-                                                 ethanediol, hexanediol and                                                     nonanedioic (azelaic) acid.                                   Available from   Formed by reacting and                                        E. I. Du Pont de Nemours &                                                                      polymerizing isophthalic acid,                                Company          terephthalic acid, 1,2-ethane-                                                 diol, butanediol and azelaic                                                   acid.                                                         Available7"      A polyester formed by reacting                                from The Goodyear Tire &                                                                        dimethyl terephthalate,                                       Rubber Company   isophthalic acid, azelaic                                                      acid, ethylene glycol and                                                      neopentyl glycol.                                             Available33"     A trifunctional polyester                                     from The Goodyear Tire &                                                                        formed principally by                                         Rubber Company   reacting dimethyl terephthalate,                                               isophthalic acid, azelaic acid,                                                ethylene glycol, neopentyl                                                     glycol and tetramethylene glycol.                             Available-200"   A polyester formed by reacting                                from The Goodyear Tire &                                                                        dimethyl terephthalate, iso-                                  Rubber Company   phthalic acid, ethylene glycol                                                 and neopentyl glycol.                                         ______________________________________                                    

These polyesters will be referred to hereinafter in the examples by the abbreviations "49000", "49001", "Vitel 307", "Vitel 5833" and "Vitel PE-200" respectively. These resins, as commercially available, contain about 0.1-0.3% moisture. This moisture content had no adverse effect on the properties of the adhesives of this invention.

The dibasic acids from which the thermoplastic polyesters are formed may be isophthalic acid, terephthalic acid, hexahydrophthalic acid, or a saturated dibasic acid having the formula HOOC(CH₂)_(n) COOH where n is an integer from 1 to 8, such as malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic and sebacic acid, or mixtures thereof.

The glycol with which the dibasic acid, or acids, may be reacted can be a diglycol having the formula HO(CH₂)_(x) OH where x is an integer from 2 to 10. Included in this group are ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and the like. Triols such as glycerin and branched diols such as neopentyl glycol are also operable.

The adhesives of the present invention are formed by reacting the Silane with the polyester such that substantially no free NCO remains in the adhesive. This is accomplished conveniently by heating an admixture of these components in a solvent system whereby the Silane is reacted through its NCO group with the polyester to form the final composition. Solvents such as toluene, methyl ethyl ketone, cellosolve acetate, and a variety of aromatic, oxygenated and esterified solvents may be employed.

Polyester adhesives, in present industrial practice, are used to adhere polyester film (polyethylene terephthalate) to polyester film. Although as evidenced in some of the following examples, polyester adhesives will adhere polyester film to glass, these adhesives offer almost no bond strength upon exposure to humid conditions. Also apparent from several examples hereinafter set forth, monomeric Silane mixed (but not reacted) with polyester will function to adhere polyester film to glass, but the performance is inferior to and less constant in its behavior than when the Silane is introduced into the polymer by reaction.

A further constraint on the use of the Silane in its free form is its volatility (equivalent to butyl acetate), making it difficult to retain in the coated film when subjected to forced air heating. As previously noted, Silane is also extremely toxic. Suitable polyurethane catalysts for the Silane-polyester reaction are the tin compounds, such as dibutyl tin diacetate, although other suitable catalysts may be used. These include the following: the stannous salts of carboxylic acids, such as stannous octoate, stannous oleate, stannous acetate and stannous laurate; dialkyltin oxides; trialkyltin oxides, tertiary amines; and tin mercaptides such as di-n-octyltin mercaptide; dialkyltin dicarboxylates such as dibutyltin dilaurate, dibutyltin diacetate, dilauryltin diacetate, dibutyltin di(2-ethylhexanoate). Of course, it is possible to use other suitable catalysts which are known to those skilled in the art.

In view of the fact that one of the principal uses of the present adhesive is to adhere solar film to window glass, it is desirable, although not necessary, to include an ultraviolet light absorber in the adhesive which is coated onto the film. A variety of such ultraviolet absorbers is available and includes a substituted benzotriazole available under the trademark "Tinuvin 328" from the Ciba-Geigy Company. In the examples which are hereinafter set forth, Tinuvin 328, in small quantities, is used as the ultraviolet absorber.

In the present adhesive, the concentration of Silane, based on thermoplastic polyester reactant, may range from as little as 0.2% to as much as 25% or more. This ratio is not critical as excellent bond strengths are obtained over the entire range and the upper limit is dictated by cost considerations which arise by using more of the Silane than is necessary for effective performance.

The present invention also relates to a method for preparing a water-activatable adhesive comprising reacting Silane with a thermoplastic polyester formed by reacting, i.e. admixing and heating, (i) a dibasic acid selected from the group consisting of terephthalic acid, isophthalic acid, and hexahydrophthalic acid and mixtures thereof, with (ii) a polymethylene glycol of the formula HO(CH₂)_(x) OH where x is an integer from 2 to 10, neopentyl glycol and glycerin, and mixtures thereof, and (iii) an aliphatic dibasic acid selected from the group consisting of those having the formula HOOC(CH₂)_(n) COOH where n is an integer from 1 to 8, and mixtures of such acids, until substantially no free isocyanate (NCO) remains in the adhesive.

In another aspect, the general invention relates to an improved sheet material for adherence to window glass for solar control, said sheet material, i.e. solar film, comprising either a single sheet of polyester dyed sufficiently to absorb the glare of bright sunlight, or a single sheet of polyester, on one side of which a reflective metal (most often aluminum) is deposited in an amount which is totally reflective or in an amount which still allows visible light transmission and over which a protective coating is deposited, or a laminated structure of the reflective film adhered to a clear or dyed polyester film by which means the reflective metal is sandwiched between two layers of polyester film, or a laminated structure of a reflective film to a polyolefin film, the improvement comprising, coated on the uncoated side of said solar film, a water-activatable adhesive comprising the reacted product of (A) Silane and (B) a polyester formed by reacting (i) a dibasic acid selected from the group consisting of terephthalic acid, isophthalic acid, and hexahydrophthalic acid and mixtures thereof, with (ii) a polymethylene glycol of the formula HO(CH₂)_(x) OH where x is an integer from 2 to 10, neopentyl glycol and glycerin, and mixtures thereof, and (iii) an aliphatic dibasic acid selected from the group consisting of those having the formula HOOC(CH₂)_(n) COOH where n is an integer from 1 to 8, and mixtures of such acids, whereby substantially no free isocyanate (NCO) remains in the adhesive.

In practice, the adhesives of the present invention are provided in an appropriate solvent system and are coated directly onto the solar film by any suitable method. The solvent is removed by force drying at a temperature in excess of about 200° F., preferably at about 230°-250° F. The coated solar film may be rolled up for storage with a release film of polypropylene or the like. For application to glass, the adhesive coated side is wetted with water, and, in addition, water is applied to the glass itself. The film is then slid into place as desired and the excess water is removed by using a squeegee. One important property of the adhesives of this invention is that they can be coated onto solar film and wound up with a release sheet into a roll and stored for long periods of time, as long as one year or more, without impairing their excellent adhesive bonding properties.

For a more complete understanding of the present invention, reference is now made to the following specific examples illustrating the improved adhesive, process and solar film of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLE 1

Polyester Solution A was prepared by dissolving the polyester resin "49,000" in a mixture of solvents according to the following formulation:

    ______________________________________                                         POLYESTER SOLUTION A                                                                          % By Weight                                                     ______________________________________                                         49,000           10                                                            Methyl ethyl ketone                                                                             50                                                            Toluene          25                                                            Methyl cellosolve                                                                               15                                                            acetate                                                                        ______________________________________                                    

Adhesive Composition A was prepared by admixing Polyester Solution A with Silane and dibutyl tin diacetate in the following proportions:

    ______________________________________                                         ADHESIVE COMPOSITION A                                                                        % By Weight                                                     ______________________________________                                         Polyester Solution A                                                                            100                                                           Silane           0.5                                                           Dibutyl tin diacetate                                                                           0.1                                                           (2% solution in                                                                toluene)                                                                       ______________________________________                                    

Adhesive Composition A was incubated for 8 days at a temperature of 140° F., after which time an infra red analysis indicated that no free isocyanate (NCO) was present. Thereafter, 1.5 parts of a 10% solution of a substituted benzotriazole ultra violet absorber, sold under the trademark "Tinuvin 328", was added to 100 parts of Adhesive Composition A.

Polyester Solution A was admixed with Silane and dibutyl tin diacetate in the following proportions to form Adhesive Composition B:

    ______________________________________                                         ADHESIVE COMPOSITION B                                                                         Parts by Weight                                                ______________________________________                                         Polyester Solution A                                                                             100                                                          Silane            2.0                                                          Dibutyl tin diacetate (2%                                                                        0.2                                                          solution in toluene)                                                           ______________________________________                                    

Adhesive Composition B was incubated for 4 days at 140° F., after which time an infra red analysis indicated that no free NCO, was present. Thereafter, 1.5 parts of a 10% solution of Tinuvin 328 was added to Adhesive Composition B.

One and one half parts of a 10% solution of Tinuvin 328 was also added to 100 parts of Polyester Solution A to provide a Control (Control A).

COATING PROCEDURE

Adhesive Composition A, Adhesive Composition B and Control A were each coated onto a dyed polyester solar film, known in the trade as "dark smoke", using a wire wound rod, and force dried at a temperature of 230°-250° F. The dried, coated film was then rolled up with a 0.75 mil. film of polypropylene as a release sheet onto a 3/4" core and stored at 95° F.

EVALUATION

After 5 months of storage, 1 inch strips of the coated polyester film were cut, wetted with water and the coated wetted side was applied to the interior surface of window glass facing Southeast at ambient room temperature.

After 5 months of exposure, the bond strength of each coated polyester film to the glass was determined by means of a Hunter gage which measures in grams per inch width the force required to peel the film from the glass at a 90° angle.

The following bond strengths were obtained:

    ______________________________________                                                       Bond Strength (grams/inch)                                       ______________________________________                                         Control A       0 - no bond                                                    Adhesive Composition A                                                                         1200                                                           Adhesive Composition B                                                                          900                                                           ______________________________________                                    

The following Table 1 summarizes the compositions of Example 1, on a solvent-free basis, and the strengths of the polyester film-glass bonds obtained:

                  TABLE 1                                                          ______________________________________                                                  Control A Adhesive A                                                                               Adhesive B                                        ______________________________________                                         49,000     10          10        10                                            Silane                 0.5       2.0                                           Dibutyl tin diace-     0.002     0.004                                         tate                                                                           Tinuvin 328 10%                                                                           0.15        0.15      0.15                                          solution                                                                       Reaction               4 days,   8 days                                        Conditions             140° F.                                                                           140° F.                                Bond       0           1200      900                                           Strength                                                                       % Silane on                                                                               0           5.0       20.0                                          Polyester Basis                                                                ______________________________________                                    

EXAMPLE 2

Polyester Solution D was prepared by dissolving "Vitel-307", and Tinuvin 328 in methyl ethyl ketone according to the following formulation:

    ______________________________________                                         POLYESTER SOLUTION D                                                                           Parts By Weight                                                ______________________________________                                         Vitel - 307       20                                                           Methyl ethyl ketone                                                                              80                                                           Tinuvin 328, 10% solution                                                                        2.0                                                          ______________________________________                                    

Polyester Solution E was prepared by admixing "Vitel 5833" with methyl ethyl ketone in the following proportions:

    ______________________________________                                         POLYESTER SOLUTION E                                                                          % By Weight                                                     ______________________________________                                         Vitel 5833       20                                                            Methyl ethyl ketone                                                                             80                                                            ______________________________________                                    

ADHESIVE COMPOSITION D

Adhesive Composition D was prepared by admixing Polyester Solution E with Silane and dibutyl tin diacetate according to the following formulation:

    ______________________________________                                         ADHESIVE COMPOSITION D                                                                       Parts By Weight                                                  ______________________________________                                         Polyester Solution E                                                                           100                                                            Silane          4                                                              Dibutyl tin diacetate                                                                          0.08                                                           NCO:OH = 1:1                                                                   ______________________________________                                    

Adhesive Composition D was incubated for 4 days at 150° F. Infra red analysis indicated that no free NCO was present. The following adhesive compositions were made by admixing Adhesive Composition D with Polyester Solution D in the indicated proportions:

    ______________________________________                                                       ADHESIVE                                                                       COMPOSITION                                                                    D-1  D-2    D-3    CONTROL                                       ______________________________________                                         Polyester Solution D                                                                           94.5   97.3   98.7 100                                         Adhesive Composition D                                                                          5.5   2.7    1.3                                              ______________________________________                                    

Each of the Adhesive compositions D-1, D-2 and D-3, plus the Control, was manually coated onto a 1 mil dark smoke dyed polyester film using a #18 wire-wound rod, followed by force drying at 230°-250° F. Coated films were wound onto a 3/4" core using a slip sheet to present blocking of the adhesive surface to the polyester film surface. After 5 days at room temperature, 1" strips of each were cut, the slip sheet removed and the coated strips were applied to the interior and to the exterior surfaces of window glass respectively, after first spraying the surface of the glass and the coated film with water to wet same.

Measurements of bond strengths were made after 2 days and 3 weeks of Southeast exposure respectively. The results obtained are set forth in the following Table 2. The measurements of bond strengths in this and in all succeeding examples were made in accordance with the procedure of Example 1.

                  TABLE 2                                                          ______________________________________                                         INTERIOR SURFACE                                                               Adhesive                                                                       Composition D-1    D-2        D-3  Control                                     ______________________________________                                         2 Days      425    200        120  50                                          3 Weeks     800    700        260  200                                         ______________________________________                                         EXTERIOR SURFACE                                                               Adhesive                                                                       Composition D-1    D-2        D-3  Control                                     ______________________________________                                         2 Days      300    270        200  0                                           3 Weeks     600    500        650  <50                                         % Silane on 1.0    0.5        0.25 0                                           polyester                                                                      basis                                                                          ______________________________________                                    

EXAMPLE 3

Adhesive Compositions E and F were prepared by admixing Polyester Solutions D and E of Example 2 respectively with Silane and dibutyl tin diacetate in the following proportions:

    ______________________________________                                         ADHESIVE COMPOSITION E                                                                          % By Weight                                                   ______________________________________                                         Polyester Solution E                                                                              100                                                         Silane             4.0                                                         Dibutyl tin diacetate (2% in                                                                      0.04                                                        toluene)                                                                       ______________________________________                                    

    ______________________________________                                         ADHESIVE COMPOSITION F                                                                          % By Weight                                                   ______________________________________                                         Polyester Solution D                                                                              100                                                         Silane             0.4                                                         Dibutyl tin diacetate (2% in                                                                      0.06                                                        toluene)                                                                       ______________________________________                                    

Adhesive Compositions E and F were each incubated for two days at a temperature of 150° F., after which time an infra red analysis showed that no free NCO was present.

The following adhesives, E-1 and EF-1, were prepared by admixing Adhesive Compositions E and F with Polyester Solutions D and E and Tinuvin 328 in the indicated proportions:

    ______________________________________                                                     ADHESIVE ADHESIVE   CON-                                                       E-1      EF-1       TROL                                           ______________________________________                                         Polyester Solution D                                                                         100        50         100                                        Polyester Solution E                17                                         Adhesive Composition E                                                                       15         9                                                     Adhesive Composition F   50                                                    Tinuvin 328   0.3        0.3        0.3                                        ______________________________________                                    

Each adhesive and the Control, were coated onto 1 mil thick dark smoke dyed polyester in the same manner as in Example 2 and then applied to the interior and exterior surfaces of window glass respectively. Measurements of bond strengths were made after 7 days, 2 weeks and 3 weeks respectively. The results obtained are set forth in Table 3.

                  TABLE 3                                                          ______________________________________                                         INTERIOR                                                                               ADHESIVE  ADHESIVE                                                             E-1       EF-1        CONTROL                                          ______________________________________                                         7 Days    575         550         220                                          2 Weeks   700         800         100                                          3 Weeks   1,300       1,200       200                                          % Silane on                                                                              2.5         2.5         0                                            Polyester Basis                                                                ______________________________________                                    

    ______________________________________                                         EXTERIOR                                                                               ADHESIVE  ADHESIVE                                                             E-1       EF-1        CONTROL                                          ______________________________________                                         7 Days    650         850         350                                          2 Weeks   1000        1,200       140                                          3 Weeks   1,300       1,100       50                                           % Silane on                                                                              2.5         2.5         0                                            Polyester Basis                                                                ______________________________________                                    

EXAMPLE 4

Polyester Solution 4A was prepared by admixing Vitel 307 with methyl ethyl ketone in the following proportions:

    ______________________________________                                         POLYESTER SOLUTION 4A                                                                         % By Weight                                                     ______________________________________                                         Vitel 307        20                                                            Methyl ethyl ketone                                                                             80                                                            ______________________________________                                    

Adhesives 4A, 4B and 4C were made by admixing Silane and dibutyl tin diacetate with Polyester Solution 4A in the following proportions:

    ______________________________________                                                   ADHESIVE ADHESIVE   ADHESIVE                                                   4A       4B         4C                                               ______________________________________                                         Polyester   100        100        100                                          Solution 4A                                                                    Silane      0.4        1.0        2.0                                          Dibutyl tin diacetate                                                                      0.06       0.08       0.1                                          (2% sol. in toluene)                                                           ______________________________________                                    

The foregoing adhesives were incubated for 2 days at 150° F., after which time no free NCO was detected upon infra red analysis. Two parts of a 10% toluene solution of ultraviolet absorber Tinuvin 328 were added to 100 parts of Polyester Solution 4A, Adhesive 4A, Adhesive 4B and Adhesive 4C respectively. Each resultant composition was then coated onto 1 mil thick dark smoke dyed polyester in the same manner as in Example 2. After storage for one week at 95° F., one inch strips of each coated film were cut, the slip sheet removed and the coated strips were applied to the interior surface of window glass after first spraying the surface of the glass and the coated film to wet same.

Measurements of bond strengths were made after 3 months of Southeast exposure. The following results were obtained:

    ______________________________________                                                 POLYESTER ADHE-    ADHE-    ADHE-                                              SOLUTION  SIVE     SIVE     SIVE                                               4A        4A       4B       4C                                         ______________________________________                                         Bond strength                                                                            700         1200     1250   1300                                     % Silane, 0           2.0      5.0    10.0                                     Polyester basis                                                                ______________________________________                                    

EXAMPLE 5

Polyester Solution E of Example 2 was admixed with Silane and dibutyl tin diacetate in the following proportions to prepare the indicated adhesives.

    ______________________________________                                                      ADHESIVE 5A                                                                               ADHESIVE 5B                                            ______________________________________                                         Polyester Solution E                                                                          100          100                                                Silane         1.4          2.8                                                Dibutyl tin    0.06         0.06                                               diacetate (2% solution)                                                        NCO:OH         1:3          2:3                                                ______________________________________                                    

The foregoing adhesives were incubated for 2 days at 150° F., after which time no free NCO was detected upon infra red analysis.

Adhesives 5C, 5D, 5E and 5F, formed from blends of Polyester Solution E and Adhesive 5A, Adhesive 5B, Adhesive 4A and Adhesive 4B respectively, each containing 2 parts of a 10% toluene solution of the ultra violet absorber Tinuvin 328, were prepared according to the following formulations.

    ______________________________________                                                ADHE-   ADHE-     ADHE-     ADHE-                                              SIVE    SIVE      SIVE      SIVE                                               5C      5D        5E        5F                                          ______________________________________                                         Polyester                                                                               100       100                                                         Solution E                                                                     (plus Tinuvin                                                                  328)                                                                           Adhesive 5A                                                                             10                  20                                                Adhesive 5B        5                 10                                        Adhesive 4A                  100                                               (plus Tinuvin                                                                  328)                                                                           Adhesive 4B                          100                                       (plus Tinuvin                                                                  328)                                                                           ______________________________________                                    

The foregoing adhesives were coated onto 1 mil thick dark smoke dyed polyester according to the procedure of Example 2. After storage for 7 days at 95° F., the coated film was adhered to the interior surface of window glass as set forth in Example 2. After 3 months of Southeast exposure, the following bond strength values were obtained.

    ______________________________________                                                 ADHE-   ADHE-     ADHE-     ADHE-                                              SIVE    SIVE      SIVE      SIVE                                               5C      5D        5E        5F                                         ______________________________________                                         Bond strength                                                                            1400      1500      1550    2000                                     % Silane, on                                                                             0.6       0.63      2.7     5.5                                      polyester basis                                                                ______________________________________                                    

EXAMPLE 6

Polyester Solution 6 was prepared by admixing Vitel 307 and methyl ethyl ketone in the following proportions:

    ______________________________________                                         POLYESTER SOLUTION 6                                                                      % By Weight                                                         ______________________________________                                         Vitel 307    20                                                                MEK          80                                                                ______________________________________                                    

Adhesives 6A, 6B, 6C, 6D, 6E, 6F and 6G were prepared by admixing Polyester Solution 6 with isocyanatopropyltriethoxy Silane and dibutyl tin diacetate in the following proportions:

    ______________________________________                                         Adhesive    6A     6B     6C   6D   6E   6F   6G                               ______________________________________                                         Polyester Solution 6                                                                       100    100    100  100  100  100  100                              Silane      0.04   0.1    0.2  0.4  1.0   3    5                               2% Dibutyl Tin                                                                             0.06   0.06   0.08 0.06 0.08 0.18 0.25                             Diacetate                                                                      ______________________________________                                    

The adhesives were incubated for 2 days at 150° F. Infrared analysis for free NCO was negative. To 100 parts of each solution, 2 parts of 10% solution of Tinuvin 328 was added.

Using a #12 wire wound rod, each adhesive was coated onto 1 mil dark smoke dyes polyester film, forced dried and wound onto a 3/4" core using 0.7 mil polypropylene as slip sheet.

After 1 week at room temperature, 1" strips were cut and, after removing the slip sheet, each coated strip was adhered to a glass panel after wetting with water. Each glass panel was then affixed to the interior surface of single glazed window exposed to the Southeast.

After 8 days, the bond strengths obtained were as follows:

    ______________________________________                                                  Adhesives                                                                      6A   6B     6C     6D   6E   6F   6G                                  ______________________________________                                         Polyester                                                                             6                                                                       Solution                                                                       Bond   150     200    650  300  320  500  950  480                             Strength                                                                       % Silane,                                                                             0       0.2    0.5  1.0  2.0  5.0   13   20                             Polyester                                                                      Basis                                                                          ______________________________________                                    

The glass panels were thereafter placed in a humidity chamber held at 90% relative humidity (RH) and 100° F. After 4 days, the glass panels were removed and the bond strengths were determined immediately after removal. The following results were obtained:

    ______________________________________                                                  Adhesives                                                                      6A   6B     6C     6D   6E   6F   6G                                  ______________________________________                                         Polyester                                                                              6                                                                      Solution                                                                       Bond    90     130    170  500  570  1100 920  490                             Strength                                                                       % Silane,                                                                              0      0.2    0.5  1.0  2.0  5.0   13   20                             polyester                                                                      basis                                                                          ______________________________________                                    

After 2 hours at ambient conditions, the bond strengths were determined again, with the following results:

    ______________________________________                                                  Adhesives                                                                      6A   6B     6C     6D   6E   6F   6G                                  ______________________________________                                         Polyester                                                                             6                                                                       Solution                                                                       Bond   140     300    500  520  570  1400 1100 680                             Strength                                                                       % Silane,                                                                             0       0.2    0.5  1.0  2.0  5.0   13   20                             polyester                                                                      basis                                                                          ______________________________________                                    

EXAMPLE 7

Polyester Solution 7 was prepared by dissolving "Vitel PE 200" in toluene, methyl ethyl ketone and methyl cellosolve acetate according to the following formulation:

    ______________________________________                                         Polyester Solution 7                                                                            % By Weight                                                   ______________________________________                                         Vitel PE 200       25                                                          Toluene            16.4                                                        Methyl ethyl ketone                                                                               50.0                                                        Methyl cellosolve acetate                                                                         8.3                                                         Tinuvin 328 (10% solution)                                                                        0.3                                                         ______________________________________                                    

Adhesive 7 was prepared according to the following formulation:

    ______________________________________                                         Adhesive 7                                                                                     % By Weight                                                    ______________________________________                                         Vitel 5833        21.7                                                         Methyl ethyl ketone                                                                              73.8                                                         Silane            4.1                                                          Dibutyl tin dilaurate                                                                            0.043                                                        (2% solution in toluene)                                                       ______________________________________                                    

Adhesive 7 was reacted under a blanket of nitrogen at a temperature of 70° C. After 44 hours, no NCO was detected upon infra red analysis. Adhesives 7A and 7B were prepared by admixing Polyester Solution 7 and Adhesive 7 in the following proportions:

    ______________________________________                                                       Adhesive 7A                                                                             Adhesive 7B                                             ______________________________________                                         Polyester Solution 7                                                                           91.0       86.0                                                Adhesive 7      9.0        14.0                                                ______________________________________                                    

Adhesives 7A, 7B and Polyester Solution 7 were each coated onto dark smoke dyed polyester film, as in Example 1, and were dried in a forced air oven at 115° C. One inch strips were cut, wetted with water and applied to glass panels which were also wetted with water.

The coated glass panels were incubated for 10 days at 120° F., after which time the bond strengths were determined. Thereafter, the coated panels were placed in a humidity chamber maintained at a temperature of 100° F. and 90% relative humidity for a period of 6 days, after which bond strengths were again determined. The results obtained were as follows:

    ______________________________________                                                 Bond Strengths                                                                                       Polyester                                                Adhesive 7A                                                                               Adhesive 7B                                                                               Solution 7                                       ______________________________________                                         10 days at                                                                               400          425        250                                          120° F.                                                                 6 days 100° F.                                                                    400          820        <50                                          and 90% R.H.                                                                   % Silane  1.2          2.3        0                                            polyester basis                                                                ______________________________________                                    

EXAMPLE 8

Polyester Solution 8 was prepared by dissolving in methyl ethyl ketone Tinuvin 328 and "49001", according to the following formula:

    ______________________________________                                         Polyester Solution 8                                                                            % By Weight                                                   ______________________________________                                         DuPont 49001       20                                                          Methyl ethyl ketone                                                                               80                                                          Tinuvin 328 - 10% solution                                                                        0.25                                                        ______________________________________                                    

adhesive 8 was prepared according to the following formulation:

    ______________________________________                                         Adhesive 8                                                                                      % By Weight                                                   ______________________________________                                         Vitel 5833         20                                                          Methyl ethyl ketone                                                                               80                                                          Silane             4                                                           2% solution of dibutyl tin                                                                        0.4                                                         diacetate                                                                      ______________________________________                                    

This solution was incubated for 4 days at 150° F. Infra red analysis indicated no free NCO.

Adhesives 8A and 8B were prepared by blending Polyester Solution 8 with Adhesive 8 as follows:

    ______________________________________                                                     Adhesive 8A                                                                             Adhesive 8B                                               ______________________________________                                         Polyester     91.7       84                                                    Solution 8                                                                     Adhesive 8    8.3        16                                                    ______________________________________                                    

Adhesives 8A and 8B, together with Polyester Solution 8, were coated onto dyed dark smoked polyester as in Example 1, and force dried at 110° C. The dried, coated polyester film was rolled up using polypropylene (0.75 mil thick) as a slip sheet.

After storage for one month at 95° F., strips of the coated film were adhered to glass panels, after first wetting the glass and the coated film, and then removing excess water.

After 3 weeks of storage at 95° F., the bond strengths of the coated glass panels were determined. The coated glass panels were then transferred to a humidity chamber and held for one month at 100° F. and 90% relative humidity, after which time bond strengths were again determined. The results obtained were as follows:

    ______________________________________                                                                       Polyester                                                Adhesive 8A                                                                               Adhesive 8B                                                                               Solution 8                                       ______________________________________                                         3 weeks - 95° F.                                                                  1250         1100       600                                          1 month 90%                                                                              950          900        50                                           R.H., 100° F.                                                           % Silane on                                                                              1.6          3.0        0                                            polyester basis                                                                ______________________________________                                    

EXAMPLE 9

Polyester Solutions 9 and 10 were prepared by dissolving "Vitel 5833" and "Vitel 307" respectively in methyl ethyl ketone according to the following formulations:

    ______________________________________                                                       Polyester                                                                               Polyester                                                             Solution 9                                                                              Solution 10                                                           % By Weight                                                                             % By Weight                                             ______________________________________                                         5833            30                                                             307                        20                                                  Methyl ethyl ketone                                                                            70         80                                                  ______________________________________                                    

Adhesives 9A, 9B, 9C, 9D and 9E, were prepared by admixing Polyester Solution 9 with Silane and a 2% solution of dibutyl tin diacetate in the following proportions, with the control (Control A) consisting of only Polyester Solution 9 and dibutyl tin diacetate

    ______________________________________                                                   Adhesives                                                                      9A   9B     9C     9D   9E   Control A                               ______________________________________                                         Polyester Solution 9                                                                       100    100    100  100  100  100                                   Silane      1.95   3.9    5.9  7.7  8.8                                        Dibutyl tin diacetate                                                                      0.06   0.06    0.06                                                                                0.08                                                                               0.1  0.06                                  (2% solution)                                                                  NCO:OH      0.33   0.67   1.0  1.3  1.5                                        ______________________________________                                    

The solutions were incubated at 140°-150° F. until no free NCO remained upon infra-red analysis. The time periods necessary to achieve this condition for each Adhesive were as follows:

    ______________________________________                                                  Adhesive                                                                       9A      9B    9C        9D  9E                                        ______________________________________                                         Time (days)                                                                               2         4     4       4   5                                       ______________________________________                                    

Even though the Control contained no Silane, it was incubated for 3 days to nullify any effects that heating may have had on the polyester.

Adhesives 9A, 9B, 9C, 9D and 9E, and the Control A were admixed with Polyester Solution 10, Tinuvin 328 and toluene in the following proportions to provide the Coating Adhesives 9B, 9C, 9D, 9E and 9F, with the control (Control B) consisting of a mixture of Control A, Polyester Solution 10, Tinuvin 328 and toluene.

    ______________________________________                                                    Coating Adhesives                                                                               Control                                                       9B   9C     9D     9E   9F    B                                     ______________________________________                                         Polyester Solution 10                                                                       100    100    100  100  100  100                                  Control A                                 7.9                                  Adhesive 9A  7.7                                                               Adhesive 9B         7.4                                                        Adhesive 9C                7.2                                                 Adhesive 9D                     7.0                                            Adhesive 9E                          7.0                                       10% sol. Tinuvin                                                                            3.4    3.4    3.4  3.4  3.4  3.4                                  328 in toluene                                                                 Toluene      2.4    2.7    2.9  3.1  3.1  2.0                                  ______________________________________                                    

The foregoing Coating Adhesives and Control B were each coated onto dark smoke polyester solar film according to the Coating Procedure of Example 1 and force-dried at 115° C.

Each coated film was slip-sheeted with polypropylene film and stored for 3 days at 95° F. The coated films were thereafter adhered to individual glass panels by wetting both the glass and the coated film, and then removing the excess water by means of a squeegee. After 4 days at 120° F., bond strength measurements were determined and recorded. The panels were then transferred to a humidity chamber and maintained there for 3 days at a temperature of 100° F. and a relative humidity of 90%. After 3 days, the bond strengths were measured. The results obtained were as follows:

    ______________________________________                                                Bond Strengths                                                                          3 days at    % Silane                                                 4 days at                                                                               100° F. & 90%                                                                        on poly-                                                 120° F.                                                                          relative humidity                                                                           ester basis                                       ______________________________________                                         Control B                                                                                280         0          0                                             Coating   700        900         0.6                                           Adhesive 9B                                                                    Coating   900       1100         1.2                                           Adhesive 9C                                                                    Coating  1100       1200         1.8                                           Adhesive 9D                                                                    Coating  1060       1260         2.3                                           Adhesive 9E                                                                    Coating  1140       1200         2.7                                           Adhesive 9F                                                                    ______________________________________                                    

EXAMPLE 10

Polyester Solution 10 was prepared as follows:

    ______________________________________                                         Polyester Solution 10                                                                         % By Weight                                                     ______________________________________                                         Vitel 307        20                                                            Methyl ethyl ketone                                                                             80                                                            ______________________________________                                    

About 5% by weight of a molecular sieve with an affinity for water, commercially available under the trade designation "Linde 4A," was added to Polyester Solution 10. After 4 days, the water content of Polyester Solution 10 was reduced to about 0.04% by weight.

Adhesive Compositions 10C, 10D, 10F, 10H and 10K were prepared by admixing Polyester Solution 10 with Silane and dibutyl tin diacetate in the following proportions and incubating the mixture at 150° F. until infra red analysis indicated that no free NCO was present. The control (Control 10B) consisted of only Polyester Solution 10 and dibutyl tin diacetate and was incubated for the same length of time as the foregoing Adhesive Compositions.

    ______________________________________                                         Adhesive Compositions       Control                                            10C         10D     10F     10H   10K   10B                                    ______________________________________                                         Polyester                                                                              100     100     100   100   100   100                                  Solution 10                                                                    Dibutyl tin                                                                    diacetate                                                                              0.06    0.06    0.06  0.08  0.08  0.06                                 (2% sol. in                                                                    toluene)                                                                       Silane  0.1     0.2     0.4   1.0   2.0                                        NCO:OH  0.5     1.0     2.0   5.0   10.0                                       ______________________________________                                    

Adhesive Composition 10L was prepared as follows, but was not subjected to incubation as were Adhesive Compositions 10C, 10D, 10F, 10H and 10K:

    ______________________________________                                         Adhesive Composition 10L                                                                      % By Weight                                                     ______________________________________                                         Polyester Solution 10                                                                           100                                                           Silane           0.4                                                           Dibutyl tin diacetate                                                                           0.06                                                          (2% in sol. toluene)                                                           NCO:OH           2.0                                                           ______________________________________                                    

Tinuvin 328 (1.5% by weight on solids basis) was added to each Adhesive Composition and also to Control 10B. Each Adhesive Composition and Control 10B were coated onto reflective smoke polyester solar film according to the procedure of Example 1 and force dried.

The coated films were wound onto a 1" core with a polypropylene slip sheet and incubated at 95° F. for one day. The coated films were then adhered to glass panels which were then attached to interior window glass facing Southeast. Bond strength values were recorded for each of the following sets of storage conditions:

    ______________________________________                                                 BOND STRENGTHS                                                                 Control                                                                               ADHESIVE COMPOSITIONS                                                   10B    10C    10D    10F  10H  10K  10L                                ______________________________________                                         2 weeks SE                                                                               525      560    420  650  1300 1190 500                              exposure                                                                       + 3 days at                                                                              0        750    720  1020 1400 1380 620                              90% RH,                                                                        100° F.                                                                 + 5 days at                                                                              450      780    850  1120 1650 1580 680                              room temp.                                                                     + 1 day at                                                                               0        640    660  870  1800 1700 510                              100° F., 100 RH                                                         % Silane (Poly-                                                                          0        0.5    1.0  2.0  5.0  10   2.0                              ester basis)                                                                   Reacted Silane                                                                           --       yes    yes  yes  yes  yes  no                               ______________________________________                                    

EXAMPLE 11

Polyester Solution 11A was prepared as follows:

    ______________________________________                                         POLYESTER SOLUTION 11A                                                                     % By Weight                                                        ______________________________________                                         Vitel 307     20                                                               Methyl ethyl  80                                                               ketone                                                                         ______________________________________                                    

Polyester Solution 11B and Adhesive Composition 11A were prepared as follows:

    ______________________________________                                         POLYESTER SOLUTION 11B                                                                      % By Weight                                                       ______________________________________                                         Vitel 5833     30                                                              Methyl ethyl   70                                                              ketone                                                                         (dried with                                                                    Linde 4A for 4                                                                 days)                                                                          ______________________________________                                    

    ______________________________________                                         ADHESIVE COMPOSITION 11A                                                                   % By Weight                                                        ______________________________________                                         Polyester     100                                                              Solution 11B                                                                   Silane        5.9                                                              Dibutyl tin   0.06                                                             diacetate (2%                                                                  solution in                                                                    toluene)                                                                       ______________________________________                                    

Polyester Solution 11B and Adhesive Composition 11 were incubated at a temperature of 140°-150° F. for 4 days, after which time no free NCO was detected by infra red analysis.

The following Coating Compositions were prepared:

    ______________________________________                                                   Coating  Coating    Coating                                                    Composition                                                                             Composition                                                                               Composition                                                11A      11B        11C                                              ______________________________________                                         Polyester                                                                      Solution 11A                                                                               100        100        100                                          Polyester                                                                      Solution 11B                                                                               10                    8.3                                          Adhesive                                                                       Composition 11A        9                                                       Tinuvin 328                                                                    (10% sol.   3.5        3.5        3.5                                          in toluene)                                                                    Toluene     5          6          6.2                                          Silane                            0.5                                          ______________________________________                                    

The Coating Compositions were coated onto the dyed polyester surface of reflective smoke polyester film according to the procedure of Example 1 and force dried. Reflective smoke polyester film is a laminate comprising a base sheet of clear polyester film, a vapor deposited coating of aluminum on one side of said base sheet with a light smoke polyester film adhered to the aluminum coating.

The dried, coated films were folled up with a polypropylene slip sheet and stored for 3 days at a temperature of 95° F., after which time the coated films were adhered to glass panels and exposed to south-east exposure sunlight by attaching the glass panels to the interior surface of window glass.

The following bond strengths were obtained after the indicated exposure conditions:

    ______________________________________                                                   Bond Strengths                                                                 Coating  Coating    Coating                                                    Composition                                                                             Composition                                                                               Composition                                                11A      11B        11C                                              ______________________________________                                         3 days      330        490        310                                          3 days at 90%                                                                              0          1150       500                                          R.H. & 100° F.                                                          1 month at  490        1800       700                                          room temperature                                                               1 day at 100%                                                                              0          700        250                                          R.H. & 100° F.                                                          % Silane    0          2.1        2.1                                          (Polyester Basis)                                                              Reacted Silane                                                                             None       Yes        No                                                       present                                                            ______________________________________                                    

EXAMPLE 12

A 2 mil. polyester film, metallized to a high opacity (optical density of 3.7) so as to reflect a maximum of incident light and thereby function as a mirror, was coated on the metal surface thereof with an acrylic resin protective coating containing the ultra violet absorber Tinuvin 328.

This protectively coated, metallized polyester film is hereinafter referred to as "The Film".

The reverse side, i.e., the uncoated polyester surface, of one sheet of The Film was coated with Control 10B, as described in Example 10. The reverse side of a second sheet of The Film was coated with Adhesive Composition 10F, as described in Example 10.

Duplicate specimens of The Film coated respectively with Control 10B and Adhesive Composition 10F were adhered to glass panels to form film-glass panel laminates, using water and a squeegee, after which time the glass panel laminates were incubated at 95° F. for 3 days. The following bond strength values of said film-glass panel laminates were obtained:

    ______________________________________                                         Bond Strengths - 95° F., 3 days                                                   Control 10B                                                                              Adhesive Composition 10F                                   ______________________________________                                                     370         1020                                                   % Silane (polyester                                                                         0          2.0                                                    basis)                                                                         ______________________________________                                    

In another experiment, one pair of said film-glass panel laminates was exposed to a temperature of 100° F. and 100% RH for one hour. A second pair of said film-glass panel laminates was exposed outdoors at an inclination of 30° from the vertical for 4 days, during which time 3 heavy rainfall downpours occurred. The resultant bond strengths were as follows:

    ______________________________________                                         Bond Strengths                                                                 Control 10B Adhesive Composition 10F                                           ______________________________________                                         100° F., 100% RH                                                        0           800                                                                4 Days Outdoors                                                                0           900                                                                ______________________________________                                    

In the outdoor exposure, a heavy orange skin-like peel developed on The Film adhered to the glass by Control 10B, whereas The Film adhered to the glass by Adhesive Composition 10F remained smooth.

Thus, The Film adhered to glass with an adhesive containing the reacted Silane lends itself to being useful in the design of solar concentrators and heliostats whose reflective surfaces can be installed in the field and replaced when solar exposure diminishes the reflectivity of the top coated metallized surface.

EXAMPLE 13

A 2 mil. polyester film having a coating thereon of vapordeposited aluminum was coated on the aluminum side with the Control 10B composition of Example 10, according to the coating procedure described in Example 1. Another specimen of the same film was coated in the same manner on the aluminum side with Adhesive Composition 10F of Example 10. Each metallized and coated film was adhered to a glass panel in the usual manner, i.e., by wetting both the adhesive coating and the glass panel and using a squeegee. The following bond values were determined after storage under the indicated exposure conditions:

    ______________________________________                                                  Bond Strengths                                                        Exposure   Control 10B                                                                               Adhesive Composition 10F                                 ______________________________________                                         4 days                                                                         95° F.                                                                             500        550                                                      1 day -                                                                        90% R.H.,   50        660                                                      100° F.                                                                 4 days -                                                                       90% R.H.,   0         1400                                                     100° F.                                                                 1 day -                                                                        100% R.H.,  0         1100                                                     100° F.                                                                 ______________________________________                                    

Optical density measurements were made (by means of a Densicron Photometer) on the glass panels coated with the film adhered by Control 10B and that adhered by Adhesive Composition 10F respectively, both before and after the above described exposures to determine the extent of loss, if any, of the aluminum deposit. There was considerable loss of aluminum on the Control 10B-coated film adhered to glass, whereas the Adhesive Composition 10F-coated film adhered to glass showed no aluminum loss, as evidenced by the following optical density readings:

    ______________________________________                                                   Optical Density                                                                Control 10B-                                                                            Adhesive Composition                                                  Coated Film                                                                             10F-coated Film                                             ______________________________________                                         Before      2.7        2.8                                                     weathering*                                                                    After       2.1        2.8                                                     weathering*                                                                    ______________________________________                                          *Exposure to high humidity and 100° F. temperature.               

In view of the fact that the optical density scale is a logarithmic one, a decrease of 0.6 optical density units for the Control 10B-coated film represents a considerable loss of the aluminum deposit. The retention of the aluminum coating in the instance of the Adhesive Composition 10F indicates the protective nature of the adhesives of the present invention. 

What is claimed is:
 1. An adhesive comprising the reacted product of(A) gamma-isocyanatopropyltriethoxy silane and (B) a thermoplastic polyester formed by reacting (i) a dibasic acid selected from the group consisting of terephthalic acid, isophthalic acid, and hexahydrophthalic acid and mixtures thereof, with (ii) a polymethylene glycol of the formula HO(CH₂)_(x) OH where x is an integer from 2 to 10, neopentyl glycol or glycerin, and mixtures thereof, and (iii) an aliphatic dibasic acid selected from the group consisting of those having the formula HOOC(CH₂)_(n) COOH where n is an integer from 1 to 8, and mixtures of such acids whereby substantially no free isocyanate (NCO) remains in the adhesive.
 2. The composition of claim 1 wherein the percent of gamma-isocyanatopropyltriethoxy silane ranges from about 0.2% to about 25% by weight of said polyester.
 3. The adhesive of claim 1 wherein the dibasic acids are terephthalic and isophthalic acids, the aliphatic dibasic acid is azelaic acid and the glycols are 1,2-ethanediol and hexanediol.
 4. The adhesive of claim 1 wherein the dibasic acids are terephthalic and isophthalic acids, the aliphatic dibasic acid is azelaic acid, and the glycols are 1,2-ethanediol and butanediol.
 5. The adhesive of claim 1 wherein the dibasic acids are terephthalic and isophthalic acids, the aliphatic dibasic acid is azelaic acid and the glycols are 1,2-ethanediol and neopentyl glycol.
 6. The adhesive of claim 1 wherein the dibasic acids are terephthalic and isophthalic acids, the aliphatic dibasic acid is azelaic acid, and the glycols are 1,2-ethanediol, neopentyl glycol and tetramethylene glycol.
 7. A method for preparing an adhesive useful for adhering a polyester film to glass, said method comprising reacting gamma-isocyanatopropyltriethoxy silane with a thermoplastic polyester formed by reacting (i) a dibasic acid selected from the group consisting of terephthalic acid, isophthalic acid, and hexahydrophthalic acid and mixtures thereof, with (ii) a polymethylene glycol of the formula HO(CH₂)_(x) OH where x is an integer from 2 to 10, neopentyl glycol or glycerin, and mixtures thereof, and (iii) an aliphatic dibasic acid selected from the group consisting of those having the formula HOOC(CH₂)_(n) COOH where n is an integer from 1 to 8, and mixtues of such acids, until substantially no free isocyanate (NCO) remains in the adhesive.
 8. A method for preparing an adhesive useful for adhering a polyester film to glass, said method comprising reacting gamma-isocyanatopropyltriethoxy silane with a thermoplastic polyester formed by reacting (i) a dibasic acid selected from the group consisting of terephthalic acid, isophthalic acid, and hexahydrophthalic acid and mixtures thereof, with (ii) a polymethylene glycol of the formula HO(CH₂)_(x) OH where x is an integer from 2 to 10, neopentyl glycol or glycerin, and mixtures thereof, and (iii) an aliphatic dibasic acid selected from the group consisting of those having the formula HOOC(CH₂)_(n) COOH where n is an integer from 1 to 8, and mixtures of such acids, until substantially no free isocyanate (NCO) remains in the adhesive, and wherein the percent of gamma-isocyanatopropyltriethoxy silane ranges from about 0.2% to about 25% by weight of said polyester.
 9. The method of claim 8 wherein the dibasic acids are terephthalic and isophthalic acids, the aliphatic dibasic acid is azelaic acid, and the glycols are 1,2-ethanediol and hexanediol.
 10. The method of claim 8 wherein the dibasic acids are terephthalic and isophthalic acids, the aliphatic dibasic acid is azelaic acid, and the glycols are 1,2-ethanediol and butanediol.
 11. The method of claim 8 wherein the dibasic acids are terephthalic and isophthalic acids, the aliphatic dibasic acid is azelaic acid, and the glycols are 1,2-ethanediol and neopentyl glycol.
 12. The method of claim 8 wherein the dibasic acids are terephthalic and isophthalic acids, the aliphatic dibasic acid is azelaic acid, and the glycols are 1,2-ethanediol, neopentyl glycol and tetramethylene glycol. 